Process of manufacturing caustic alkalies and zinc sulfid.



Elm-818,192. PATENTED APR.17, 1906. 0. RANSON.

PROCESS OF MANUFACTURING OAUSTIC ALKALIES AND ZINC SULPID.

APPLICATION FILED 0011.3. 1904 2 SHBETSSHEET lv Figft.

PROCESS OF MANUPAG PATENTED APR. 17, 1906.

O. RANSON. v TUBING CAUSTIC ALKALIES AND APPLICATION FILED 0OT.3.1904.

ZINC SULFID.

Z SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE T CHARLES RANSON, or BRUSSELS, BELGIUM, ASSIGNOR TO HENRY WILLIAM DE. STUCKLE, or DIEUZE, GERMANY.

PROCESS OF. MANUFACTURING CAUSTIC ALKALIESAND zmc SULFIIf).

aSpecification of Letters Patent.

- Patented April 17, 1906.

Application filed October 3, 1904 Serial No. 227,075;

gium, have invented certain new and useful Improvements in Processes of Manufacturing I Caustic Alkalies and Zinc Sulfid, of which the following is a specification.

The present invention relates to the manufacture of caustic alkalies or alkali-hydrates, such as potassium or sodium-hydrate, the obj ect of the said invention bein to furnish a method of obtaining these alka compounds in an economical manner from readily-available startin materials and so that commercially valua le by-products will'result;

With these objects in view the invention involves the treatment of alkali sulfid with zincin the presence of alkali hydrate. This treatment, as has beenfound by the inventor leads to the very advantageous and im or tant result that coincidently with the pro uction of the alkali hydrates zinc sulfid of a fineness and purity hitherto unattainable is obtained. 4 My invention also involves the features and steps hereinafter to be described.

Under this invention the zinc and alkali hydrate react upon each other in the presence of alkali sulfid. The evolution of hydro en due to such reactiontherefore always ta es place in the presence of such alkali sulfid. This is of special importance'for the production of the final products, because in this manner, as I have found, it alone becomes possible to obtain zinc sulfid of-superior quality, which by virtue of the evolution of hydrogen which continually takes place during its ormation is obtained in a finelydivided state and in copious volunfe. It is therefore more valuable as paint or pigment and forms a more effective coating than zinc sulfid Which has been precipitated without such evolution of hydrogen. This is not the only useful result due to the evolution of hydrogen; but the same can be utilized to erform the further useful function of-regu ating the progre'ss of the process in such a way as to render the same continuous and without interruption.

The development of hydrogen fur rushes a very convenient means for ascertaining at all times whether or not alkali sulfid is present in excess. It is to be observed that such excess must be carefully avoided, since would be interru ted andthe continuity of the same rendered impossible whereby an inferior final product would result.

Under my invention, it should be observed, alkali hydrate is continually regenerated simultaneously with the formation of zinc sulfid. If now more alkalisulfid is present than necessary for the formation of zinc sulfid, the alkali sulfid is decomposed in the 'hot solution, such decomposition being accom ained by the evolution of hydrogensulfi gas. This hydrogen sulfid reacts upon the alkali hydrate present, forming sulfid and sulfhydrate of the alkali and consumes the alkali hydrate,- which is avery undesirable result, for the reason that thereby such alkali hlydrateis diverted from its-proper function 0 otherwise the regular progress of the reaction 1 dissolvin zinc and developing hydrogeni Moreover, t e sulfhydrates thusformed are easily decomposed, and thereby color the pre-' cipitated zinc sulfid yellow, thus rendering it worthless. The proper addition of the alkali sulfid is also of importance, for the reason that if the-alkali sulfid is not added while undecomposed alkali hydrate is present in the re-l ceptacle in which theireaction takes place the 'continuityofthe operation will be interrupted.

In order that the evolution of hydrogen is continuousand is never interrupted, an excess of zinc is employed, In consequence of this excess of zinc the primarily-formed alkali hydrate will always be in presence of zinc to be dissolved, so that .a continuous formation of zinc-alkali oXid takes place Hence'the alkali sulfid can continually react uponzinc-alkalioxid, and thus the continu ity of the operation ismaintained. In order to utilize the evolution of hydrogen as a regulator of the amount of alkali sulfid to be added, the starting materials are treated in an air-tight closed receptacle for the urpose of retaining andmeasuring. the deve oped hydrogen. The observation of the amount of hydrogen formed furnishes a criterion for the proper progress of the reaction and for determining the period at which further quantities of'alkali sulfid are to be added. The evolution of hydrogen -may servenot only as an indicator but also as a means for operating automaticmechanism for regulating the supply of the alkali 45 structed and arranged in any desired manner,

' sulfid to the receptacle in which the reaction evolution of hydrogen, and hence the continusurfaces to the reaction liquid, the receiver or walls.

' fid, the receptacle in which the reaction takes containing the alkali sulfid that the supply of takes place.

In order to maintaln the uninterrupted ity of the reaction, it is necessary to prevent the deposition of the fine particles of zinc sulfid which are suspended in the liquid upon the metallic zinc and coverin the same with an isolating layer, which won (1 render the solution of metallic zinc difficult, if not impossible. For this purpose the receptacle in which the reaction takes place is provided with an agitating device to which the-continuous movement can be imparted and which at the same time is so arranged that the metallic zinc may be distributed over a large surface. One way of carrying this into effect is by placing themetallic zinc in a divided or granular form into an iron receiver or drum mounted upon a rotary shaft. By revolving the receiver the necessary agitating or stirring effect is obtained. In orderthat the zinc sulfid is not permanently deposited upcn the zinc, but remains in suspensicn. or is carried off after being formed for the purpose of continuously presenting new metallic drum is formed of a erforated or foraminated bottom and simi ar walls, so as to present substantially the shape of a dished strainer. Under such a construction the reaction liquid will flow toward and over the zinc from all sides and carry off the deposit. In order to facilitate the penetration of the reaction liquid between the-zinc particles, the interior of the dished foraminated iron drum is divided into a number of compartments by iron perforated or foraminated partition- By such a construction the liquid can pass from one compartment to the other, and, moreover, the surface of metallic iron is greatly increased. Thereby the zinc is at all arts in contact with the iron, and thus its soution is facilitated, accordingto well-known principles. The partition-walls may be coneither radially or radially with transverse dividing-walls in the radial partitions or in any other desired or suitable-manner.

In order to prevent an excess of alkali sulplace is so connected with the feed-receptacle said alkali sulfid is governed by the amount ofigghydrogen developed. For this purpose aff automatic pressure-regulator is arranged; in communication with the receptacle s to permit the access of the hydrogen the and is connected with regulating means, such as a valve in the supply-pipe connecting the the alkali-sulfid receptacle with the receptacle in which the reaction takes'pla'ce.

If it is desired to obtain caustic alkali and zinc sulfid simultaneously, zinc in excessis boiled with caustic alkali in the closed metallic receiver, iron filings being added for facilitating the evolution of hydro en. Any suitable device maybe employed or heating the recepta'clesuch as, for example, a double bottom,'as shownfor the introduction o'fa heating medium, such as steam, a steam-coil, or thelike.

In starting the process the desired'amount of zinc is first dissolved and care is taken that undecomposed alkali hydrate is still resent. Thereupon the alkalisulfid is gradua ly added, the stirring or agitating device being in constant motion in order to prevent the finely-divided suspended zinc sulfid from settling to the bottom. Hence during the course of the process zinc, caustic alkali, and alkali sulfid are simultaneously present in the reaction-receptacle. The supply of the alkali sulfid is so regulated that the amount of the same is ust sufficient to form the zinc sulfid, and'no excess of the same, which, as formerly stated, would be injurious, is present. After the reaction is completed ,r-nly a portion of the contents of the receptacle is removed.

According to E nation 1 it will be. noted zinc-sodium; oxid n(ONa) is first. formed,

which zinc-sodium oxid is in turn acted upon by the sodium sulfid to form zincsulfid and sodium hydrate or caustic soda. This reastion proceeds accordingtothe equation:

the pur ose of this reaction just suflicient sodium sul dis added as is necessary to convert the zinc-sodium oxid'into zinc sulfid and caustic soda. would have the result that such excess would An. excess of sodium sulfid IIC react upon the sodium hydrate in an unde- "sired manner and would be attended by the formation of'sodium sulfhydrate and hydrogen sulfid.

While I have hereinbefore described my process as applicable in connection with alali hydrates, it is to be observed that it may be carried out also for the roduction of hydrates of the alkaline-cart 'metals, and for this purposeinstead ofthe alkali hydrates I tomand similar walls.

and alkali sulfidsthe hydrates and the sulfids of' alkaline-earth metals are to be employed and they are to be considered as the equivalents of the former. (Referred to in the specification and the claims.) For carry ing out this process I have devised an ap aratus which is especially suitableand which is illustrated in the-accompanying drawings.

In .the said drawings, Figure 1 is an elevation, partly in longitudinal vertical section, of suchapparatus. Fig. 2 is a sectional plan on line AA of Fig. 1, onehalf of the same being represented broken away; Fig. 3, a similar view showing a .modified form of -drum. Fig. 4 is a longitudinal vertical section of the regulating device. v

a is the receptacle in which the granulated zinc in excess and caustic alkali are heated by introducing steam or another medium into the double bottom a.

b is the rotary drum of a perforated bot- The drum is divided into compartments by perforated radial partition-walls g and 1', Fig. 2, or by radial partition-wall t and transverse dividing-walls u,

Fi 3. Referring to Fig. 2, the partition wa ls r are extended to the axis, whereas the intermediate partitions reach only to the The drum 1) is secured to a vertical shaft 0, resting in the bottom bearing 0, intermediate bearin '0 and upper bea'ring 0 f The upper end 0 the shaft 0 has-secured thereto a bevelear d, 'meshin with the bevel-gear e on the s aft e, to whic is secured the fixed and loose pulleys ff. By driving the pulley f the rotation is transferred, by means of the gears e d, to th I shaft sand to the drum 7).

The receptacle a is, hermetically closed by the cover a through which the tubes 9 and it pass. The tube, h is supported by the bracket it, connected to the bottom housingi of the regulator, and may be opened or closed 7 by the valve m, connected to the rod Z. The rod Zis shiftably supported by the eye Z of the arm 1 and connected to the lever 7c, the

fulcrum of which is at k; The other end of the lever is is connected to a float 1 by means of the rod 2 within the upper housing 3 of the regulator, which housing is supported by rods 4, resting on the bottom housin i. The bottom housing '1', is connected Wltlffilfl u er housing 3 by means of a tube 5 and isill ed with water to the level y y. The space above the level y y is connected by the tube 9 with the upper part of the rece tacle a... The receptac the tube a.

If hydrogen is disengaged in the receptacle a, it escapes through the tube 9 into the bottomxre'ceptacle i of the regulator and presses upon the water-surface, so that the water mounts through the tube 5 into the upper rev upon the comes weaker.

e 1), containing alka i sulfid, is' connect- 1 ed to the housing of the valve m by means 'of drates, which consists in heating zinc in exceptacle 3 and lifts the flo'atl ,rod 2, and lever 7c, which will turn about its fulcrum 7c, move down the rod 1, and press the valve m on its seat, so that no alkali sulfid will be fed into the rece tacle'a. If the development ofhydrogen e ins to cease, the-pressure acting Then the-float Zsinks down,

evel y 'y'by the hydrogen gas-beturns the lever k, lifts therod 1, and opens I the valve m, so that alkali sulfid is fed through the tubes n and 7t into the receptacle 0..

The zinc sulfid which is obtained with the employment of' alkali hydrates is preferable,

on account of its greater whiteness, to thatobtained by employing the hydrates of the alkaline-earth meta s,'for the reason that for the Z1110 sulfid 'remams contaminated by the barium hydrate by reason of the low solubility of the latter.

The present process results in a veryfine white zinc sulfid which is very impalpable and soft to the touch, and therefore possesses a much higher coating capacity than the products hitherto obtained. It 18 to be noted, moreover, that the resulting solutions of alkali hydrates or alkaline-earth hydrates are of a very high percenta e. For example, a caustic-soda so ution o a stren th of 35 Baum may be obtained directy by this 9's process.

What I claim,

and desireto secure by Letters Patent, is-- 8'0 example, when employing barium hydrate I 1. Theprocess of manufacturing alkali hy- I drates, which consists in treating zinc in the presence of alkali hydrate with alkali sulfid.

' 2. The process of manufacturing alkali hydrates, which consists in heating zinc in excess in the presence of alkali hydrates with alkali sulfid.

3. The process of manufacturing alkali hy-.

drates, consisting'in heating zinc in' the pres" ence of alkali hydrates with alkali sulfid, which is, added inja quantity no greaterthan necessary for transforming zinc alkali oxid into zinc sulfid and-caustlc alkali.

' 4. The process of manufacturing alkali hydrates, consistin in treating zinc 1n excess in the presence of a kali hydrates with alkali sulfid, the alkali sulfid being added ina quantity no greater than necessary for transforming zinc-sodium oxid into zinc sulfid and caustic alkali.

5. The process of manufacturing alkali hydrates, which consists in treating zinc in the. presence of alkali hydrate with alkali sulfid and. keeping the precipitate in suspension. 6. The process of manufacturing alkali hycess'in the presence of alkali hydrate with alkali sulfid and keeping the precipitate in suspension. I

7. The rocess of manufacturingalkali hydrates, w ch consists in heating zinc in the 5 ing the precipitate in sus ension. n'esses.

presence of alkali hydrates with alkali sulfid, alkali into zinc sulfid and caustic alkali and.

which is added in a quantity no greater than keeping the preci itate in suspension. necessary .fcr transforming zinc-alkali oxid In testimony w ereof I have hereunto set into zlnc sulfid and caustic alkali and keepmy hand in presence ofv twp subscribing witelgrocess 0f manu acturing alkali hydrates, W ich consists in treatingzinc in exl l cess 1n the presence of alkali hydrates with Witnesses:

alkali sulfid, which is added in a quantity n6 l CHL. DE Vos,

CHARLES RANSON..

10 greater than necessary for transforming zinc JUSENDE. 

